What is the Origin of Neuronal Excitability?

This is a core concept in neurophysiology and cellular biology, rooted in the classic Hodgkin-Huxley model of the action potential. The term is derived from 'neuronal' for nerve cell and 'excitability,' referring to the ability to be excited or stimulated. Its study involves the biophysics of ion channels and membrane potentials.

What is the Mechanism of Neuronal Excitability?

The mechanism is primarily driven by voltage-gated ion channels, particularly those for sodium and potassium, embedded in the neuronal membrane. A depolarizing stimulus reaches a threshold, causing a rapid influx of sodium ions that generates the action potential. Repolarization follows with the efflux of potassium ions, returning the membrane potential to its resting state. Hormones like thyroid hormones and sex steroids can modulate this process by altering the expression or function of these critical ion channels, thereby fine-tuning the overall excitability of neural circuits.

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Neuronal Excitability

Meaning

Neuronal excitability is the fundamental intrinsic property of a neuron to generate and propagate an electrical signal, known as an action potential, in response to a stimulus. This property is the basis of all nervous system communication, governing processes from simple reflexes to complex cognitive functions. The level of excitability is precisely controlled by the balance of ion flow across the neuronal membrane. Dysregulation of neuronal excitability is implicated in various neurological disorders, including epilepsy, and can be subtly influenced by circulating hormones.